Coffee filter element



COFFEE F ILTER ELEMENT Original Filed Got. 19, 1.9.66

FIG.2-

INVENTOR ERWIN HARVITH BY ATTORNEYS United States Patent 3,360,132COFFEE FILTER ELEMENT Erwin Harvith, Sonthfield, Mich., assignor to StarFilter Company, Detroit, Mich., a corporation of Michigan Originalapplication Oct. 19, 1966, Ser. No. 586,264, now

Patent No. 3,343,682, dated Sept. 26, 1967. Divided and this applicationJune 5, 1967, Ser. No. 643,235

' 5 Claims. (Cl. 210--477) ABSTRACT OF THE DISCLOSURE A coffee filterfor insertion in a basket of perforated cup of coffee-making apparatusincluding a central accurate slit to permit the filter to be insertedover the central stem of a percolator or to lie flat on the bottom ofthe basket when used in a dripulator and in which the filter alsoincludes a peripheral tear strip so that it will accommodate differentsizes of baskets.

The present application is a divisional application of Ser. No. 586,264filed Oct. 19, 1966, now Patent No. 3,343,682, which in turn was acontinuation-in-part ap plication of copending but now abandonedapplication Ser. No. 300,947 filed Aug. 8, 1963.

Coffee making apparatus normally comprises a perforated cup or basket inwhich a filter element is placed. Ground coffee beans are disposed inthe basket on top of the filter element and means provided to causeheated water to spill over onto the coffee. As the water tricklesthrough the loose coffee grounds, it absorbs the fiavor and strength ofthe coffee beans. The filter element is normally formed of a paper ortissue material adapted to remove the fine grounds or dregs which wouldnormally pass through the perforations in the ground coffee containingbasket in the absence of the filter.

A problem associated with conventional coffee filters is that coffeepercolators in common usage, depending on their capacity, normallyemploy a variety of sizes of coffee baskets. Thus, the retailer isrequired to maintain an inventory of coffee filters to accommodatedifferent sizes of percolators. In addition, a consumer having coffeepercolators of two different sizes is required to maintain a stock oftwo different sizes of coffee filters.

It is the broad purpose of the present invention to pro vide a coffeefilter sheet which may be adapted to accommodate any standard sizecoffee ground basket. In a preferred embodiment of the presentinvention, which will be subsequently described in detail, the filtersheet is formed of filter material and provided with a series ofcircular patterns having a common diameter with each patterncorresponding to a standard size coffee basket. Each circular pattern isdefined by a series of incisions formed in the filter material andadapted to permit separation of the circumferential edge of the filtersheet so that the diameter of the element is reduced to the desiredsize. Thus, one size filter sheet can be adapted to accommodate anystandard size ground coffee basket thereby reducing the varieties ofsizes of coffee filters which must be maintained by the retailer and theconsumer.

There are two different types of coffee making apparatus in commonusage, including the percolator type which employs a perforated baskethaving a hollow stem extending therethrough for the delivery of heatedwater which spills over the ground coffee. A second type of coffee makeris the dripulator, Which employs a perforated basket and means forpouring the water over the ground coffee without utilizing a hollowstem.

It is another purpose of the present invention to provide a singlefilter which in addition to accommodating 3,360,132 Patented Dec. 26',1967 any standard size of coffee basket can be used with either of theabove common type coffee makers. The preferred embodiment of theinvention employs a centrally disposed incision which will permit a stemto be slipped therethrough or remain seated in the plane of the filterif a stem is not utilized. Preferably the centrally disposed incisiontakes the form of an arcuate incision having a diameter closelycorresponding to the diameter of the stern so that when the filterelement is slipped over the stem, the filter forms a snug fit thuspreventing the grounds from slipping through with the dripping water.Another form of the centrally disposed slit to accommodate the hollowstem takes the form of a pair of mutually perpendicular incisions, whichpermit the filter to be inserted over the end of the stern. Although theperpendicular incisions are of a more conventional configuration, thearcuate incision provides special advantages over the conventionalconfiguration in that there is little tendency for the incision to tearradially outwardly; thus, enlarging the central opening and permittingthe grounds to slip through around the hollow stem.

It is therefore an object of the present invention to provide a singlesize filter sheet which is provided with a plurality of circularpatterns perforated to permit the filter sheet to be reduced to a sizecorresponding to the diameter of any standard coffee ground basket.

It is another object of the present invention to provide such a filterhaving an extremely simple design and low manufacturing costs.

It is still another object of the present invention to 1 provide such afilter which may be utilized in coffee making apparatus employing abasket either with or without a centrally disposed hollow sternextending therethrough.

Still, other objects and advantages of the present invention will befully apparent from the following detailed description wherein thepreferred embodiment of the invention is set forth. The invention makesreference to the accompanying drawings in which:

FIG. 1 is a plan view of the preferred filter element embodying theinvention;

FIG. 2 is a side elevation view of the element illustrated in FIG. 1;

FIG. 3 is a perspective view of the element illustrated in FIG. 1 andshowing how the element may be reduced to a select size; and

FIG. 4 is a perspective view of the element of the reduced element beinginserted in the basket of a coffee brewing apparatus.

Now referring to the drawings, FIGS. 1 and 2 illustrate a preferredembodiment of the present invention as comprising a filter sheet 10formed of conventional filter material, such as tissue. The filter sheet10 preferably has a circular configuration and includes three circularpatterns 12, 14, and 16; each having a decreasing diameter and formedabout a common center. Each of the patterns is preferably defined by aseries of spaced incisions to form a circumferential tear strip.Preferably each of the patterns correspond to the diameter ofconventional coffee filter basket. Thus, for instance, pattern 16 mighthave a diameter of three inches, pattern 14, a diameter of three and onehalf inches, and pattern 12, a diameter of four inches, and the overalldiameter of the filter sheet having a magnitude of four and one halfinches.

As can best be seen in FIG. 2, the filter sheet If) is adapted toaccommodate a selected basket size by tearing the peripheral edge of thefilter sheet along a pattern size corresponding to the selected basket.It is to be understood, of course, that the incisions of the unseparatedpatterns are such that they do not permit the cofiee grounds to tricklethrough but perform a full filtering function.

It will be noted that in FIG. 1, the element 10 is provided with a pairof centrally disposed, narrow, perpendicular slits 18. FIG. 3illustrates an alternative embodiment of the invention including afilter element 20 having circular patterns 22, 24, and 26. Thisembodiment differs from that shown in FIG. 1 in that a centrallydisposed arcuate slit 28 is employed. The slit 28 is preferably formedthrough about 300 of a circle and the remaining 60 is left unformed.When used with a dripulator, the tab thus formed remains seated to forma unitary part of the filter.

FIG. 4 illustrates a basket 36 employed in a perpendicular-type coffeemaking apparatus which utilizes a hollow vertical stem 32 extendingupwardly through the basket to direct heated water which is deliveredover the grounds contained within the basket. The filter element 20illustrated in FIG. 2 has its size reduced by removing thecircumferential edge so that its diameter corresponds to the interiordiameter of the basket 30. The filter element is then pushed over theupper end of the stem 24, so that the flap of the arcuate incision 28forms a circular opening. The filter is pushed downwardly along the stem24 until it overlays the horizontal perforated bottom of the basket 30.The ground cotfee beans are then placed in the basket over the filterand the coffee brewed in the conventional manner. After brewing, thefilter is discarded with thecoffee grounds.

Since the filter 10 fits closely about the sides of the hollow stem 32,the coffee grounds are prevented from passing through.

Having thus described my invention, I claim:

1. A filter element adapted for use with ground coffee holding basketsof different sizes, said filter element comprising:

(a) a circular planar section of a fluid pervious material;

(b) a circular pattern defined in said planar section formed by a seriesof arcuate incisions forming a circular line of separation adjacent theouter periphery thereof and corresponding to the lower portion of theground coffee holding basket so that the per- 4 imetric edge of saidplanar section may be separated along said weakened line of separationto form a circular body section to accommodate the ground coffee holdingbasket.

2. A filter element as defined in claim 1 including a second circularpattern defined by a weakened line of separation and corresponding tothe lower portion of another ground coffee holding basket, and saidfirst and second circular patterns having diameters with differentmagnitude and having a space therebetween greater than the space betweenthe arcuate incisions forming said lines of separation.

3. A filter element as defined in claim 1, including an arcuate incisioncentrally formed in said section, said central arcuate incision having agenerally semi-circular configuration with all points parallel to saidcircular patterns so that said filter element may be laid in a coffeeperculator having a tubular section extending through the centralarcuate incision so that the edges of the central arcuate incisionintimately contact the outer surface of the tubular section.

4. A filter element as defined in claim 1, including a centrallydisposed incision adapted to allow said filter element to be placedabout the central stern of a coffee maker.

5. A filter device as defined in claim 1, including a pair of mutuallyperpendicular centrally disposed incisions having a length slightlyexceeding the diameter of a central stem in a coffee maker and adaptedto all-ow said filter element to be placed about said central stern inthe bottom of said ground coffee basket.

References Cited UNITED STATES PATENTS 8/1960 Sisselman et al 99-31O 5/1966 Adiletta 210-477

1. A FILTER ELEMENT ADAPTED FOR USE WITH GROUND COFFEE HOLDING BASKETSOF DIFFERENT SIZES, SAID FILTER ELEMENT COMPRISING: (A) A CIRCULARPLANAR SECTION OF A FLUID PREVIOUS MATERIAL; (B) A CIRCULAR PATTERNDEFINED IN SAID PLANAR SECTION FORMED BY A SERIES OF ARCUATE INCISIONSFORMING A CIRCULAR LINE OF SEPARATION ADJACENT THE OUTER PERIPHERYTHEREOF AND CORRESPONDING TO THE LOWER PORTION OF THE GROUND COFFEEHOLDING BASKET SO THAT THE PERIMETRIC EDGE OF SAID PLANAR SECTION MAY BESEPARATED ALONG SAID WEAKENED LINE OF SEPARATION TO FORM A CIRCULAR BODYSECTION TO ACCOMMODATE THE GROUND COFFEE HOLDING BASKET.